Fabricated wear member assembly attached to a work implement using a retaining mechanism

ABSTRACT

A method of manufacturing a wear member assembly that includes a sheet metal member and a rigid member is provided. The method comprises forming the sheet metal member to a first configuration, and casting or machining the rigid member to a second configuration.

TECHNICAL FIELD

The present disclosure relates to the field of machines that perform work on a material using work implements such as earth moving machines and the like. Specifically, the present disclosure relates to wear members such as lip shrouds that protect the working edges of work implements and their associated fabrication techniques and attachment mechanisms.

BACKGROUND

During normal use on machines such as mining machines work implements such as buckets are used to move a work material such as dirt, rock, etc. Various parts of the work implement may become worn over time, necessitating their replacement. This can be costly as it requires the purchase of new components and downtime for the machine using the work implement so that the new components may be installed.

Accordingly, various devices and methods have been developed to prolong the life of a work implement. One such device is a wear member such as a lip shroud that covers a working edge such as the lip of a bucket. When this component is worn, it may be replaced without replacing the entire bucket.

However, these lip shrouds are often welded onto the bucket or are otherwise attached using an attachment system that requires the use of a hammer to strike on a retaining member so that it is installed in the locking apertures of the lip and of the lip shroud. In the case of fabricated lip shrouds, welding is only used as this is the only method that has been proven reliable with fabricated wear members such as lip shrouds. This makes replacing the lip shroud or other similarly fabricated wear member assemblies difficult.

SUMMARY OF THE DISCLOSURE

A wear member assembly that is configured to be mechanically attached to a work implement using a retaining mechanism is provided. The wear member assembly comprises a first sheet metal member that is formed to a first configuration, and a buttress member that forms a throat portion and that is connected to the upper sheet metal member. The first sheet metal member at least partially forms a reinforced attachment structure that defines an aperture that is configured to receive a retaining mechanism.

A wear member assembly that is configured to be mechanically attached to a work implement using a retaining mechanism is provided. The assembly comprises a sheet metal member and a buttress member that is attached to the sheet metal member and that forms a throat portion. The wear member assembly is manufactured using a process that comprises the following steps: bending the sheet metal member to form at least one bend, and machining or casting the buttress member to form the throat portion.

A method of manufacturing a wear member assembly that includes a sheet metal member and a rigid member is provided. The method comprises forming the sheet metal member to a first configuration, and casting or machining the rigid member to a second configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a work implement assembly in the form of a bucket including a lip, wear member assemblies in the form of lip shrouds, wing shrouds, and retention systems, according to an exemplary embodiment.

FIG. 2 is an exploded perspective view of the lip, wear member assemblies, wing shrouds, and retention systems of FIG. 1.

FIG. 3 is a top view of the wear member assembly shown in FIG. 1 shown in isolation.

FIG. 4 is a bottom view of wear member assembly of FIG. 3.

FIG. 5 is a front view of the wear member assembly of FIG. 3.

FIG. 6 is a side sectional view of the wear member assembly of FIG. 3 taken along a midplane thereof.

FIG. 7 is a front oriented perspective view of the wear member assembly of FIG. 3.

FIG. 8 is a rear view of the wear member assembly of FIG. 3.

FIG. 9 is an exploded assembly view of the wear member assembly of FIG. 3.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In some cases, a reference number will be indicated in this specification and the drawings will show the reference number followed by a letter for example, 100 a, 100 b or a prime indicator such as 100′, 100″ etc. It is to be understood that the use of letters or primes immediately after a reference number indicates that these features are similarly shaped and have similar function as is often the case when geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters or primes will often not be included herein but may be shown in the drawings to indicate duplications of features discussed within this written specification.

An exemplary embodiment of a work implement 100, e.g., a machine bucket 101, is illustrated in FIG. 1. In the exemplary embodiment, the bucket 101 may be attached to a dragline (not shown) that is configured to remove material, such as earthen material, with the bucket 101. The dragline may manipulate the bucket 101 by utilizing a hoist mechanism (not shown) and a drag mechanism (not shown) that are controlled by an operator in a machine cabin (not shown) of the dragline. Alternatively, the bucket 101 may be attached to other types of machines known in the art, such as excavators or other earth-working machines. As another alternative, the work implement may embody any device used to perform a task assigned to a machine, including but not limited to, a rake, shears, etc.

The bucket 101 may include a main body 102, which may be a box-like structure with an open top, and an open front end 104 through which the material may pass to enter the main body 102. The main body 102 may include side walls 106 that are connected by a cross beam 108. The bucket 101 may include one or more connecting mechanisms 110, e.g., one or more brackets, for connecting to chains or cables used for manipulating the bucket 101. For example, the cross beam 108 may include one or more of the connecting mechanisms 110 for connecting to one or more chains associated with the hoist mechanism, and the side walls 106 may include one or more of the connecting mechanisms 110 for connecting to one or more chains for the drag mechanism.

The bucket 101 may include a front edge assembly 112 attached to the main body 102 of the bucket 101, e.g., by welding, and may be replaceable. The front edge assembly 112 may include a lip 114 and one or more ground engaging tools (GET) attached to the lip 114, such as one or more wear members 116 such as lip shrouds, one or more wing shrouds 118, and/or a plurality of teeth 120.

FIG. 2 is an exploded view of the wear assembly 112, excluding the teeth 120, according to an exemplary embodiment. The lip 114 may also include one or more noses 122 that project forwardly from a front edge of the lip 112, and the teeth 120 (shown in FIG. 1) may attach directly or indirectly (e.g., via adapters or couplers) to the noses. In an embodiment, the teeth 120 may be two-piece components including a tip that may be connected to an adapter, e.g., by welding, a coupler, or other retaining system. The adapters may be removably connected to the respective noses via a locking pin or other retention system, such as the retention system described below. Alternatively, the GET (e.g., the wear members 116 such as lip shroud, the wing shrouds 118, and/or the teeth 120) may take any form known in the art, such as, for example, a single-piece component or multi-piece component that is removably connected to the noses, such as a fork or other multi-point configuration, a chisel or blade configuration, a blunt-end configuration, or other single-point configuration.

The terms “front” and “rear” are used herein to refer to the relative positions of the components of the exemplary front edge assembly 112 compared to their directions of assembly onto the work implement. When used herein, “front” or “forward” refers to one side of the front edge assembly 112, e.g., closer to the tips of the noses 122 of the lip 114 and/or the teeth 120 attached to the noses. In contrast, “rear” or “rearward” refers to the side of the front edge assembly 112 that is opposite the front side. The rear side of the front edge assembly 112 may be the side that is connected to the main body 102 of the bucket 101 when the front edge assembly 112 is attached to the main body 102. Similarly, “lower” and “upper” mean opposite directions along a vertical direction where “upper” refers to features higher vertically away from the front edge assembly and “lower” means features lower vertically closer to or even below the front edge assembly.

The wear members 116 and the wing shrouds 118 may protect the front edge of the lip 114. The wear members 116 may be mountable on the lip 114 between the noses, and the wing shrouds 118 may be mountable on wing plate portions of the lip 114 that extend upward (e.g., vertically or at an angle that is generally upward) relative to a central plate portion 128. As shown in FIGS. 1 and 2, the front edge assembly 112 may include five teeth 120 that are spaced apart along the length of the lip 114, four wear members 116 that are located between adjacent teeth 120, and two wing shrouds 118. Each of the teeth 120, the wear members 116, and the wing shrouds 118 may be replaceable and designed to protect a different portion of the lip 114 from abrasive wear. Alternatively, other numbers of the teeth 120, the wear members 116, and the wing shrouds 118 may be provided, depending on the application.

Each of the wear members 116 and the wing shrouds 118 may include a front edge portion that hooks over the front edge of the lip 114. Each of the wear members 116 and the wing shrouds 118 may also include a mounting portion 124 configured to receive a retention system 126 for clamping or attaching the respective wear member 116, wing shroud 118, or other GET in a removable manner to the lip 114 or other portion of a work implement. Mounting apertures 130 that are configured to receiving the retaining mechanism 126 of the wear members 116 may also be seen on the front lip. A plurality of protrusions 132 are provided that mate with complimentary shaped recesses (not shown) on the wear members 116 for locking them into place.

Looking at FIG. 2, it can be seen that the front edge 135 of the front lip 114 defines a sweep direction S, which may be curved, straight, staggered, etc. and represents the theoretical shape of the front edge 135 and is offset from the front edge 135. Focusing now on FIG. 3, the wear member assembly 116 includes a mounting tang 144 that is part of the top leg 146 of the wear member assembly 116. The mounting tang 144 defines a mounting aperture 148 that is configured to mate with a suitable retaining mechanism such as shown in FIG. 2. A series of wear plates or chocky blocks 150 are attached to the top of the wear member assembly 116 in a manner known in the art. A hoisting ring 152 is also provided that extends from the top surface of the top leg 146 of the wear member assembly 116. Also, a pair of wear plates 222 and a reinforced attachment structure 206 may be seen next to the mounting aperture 148.

Turning now to FIG. 4, a bottom view of the wear member assembly 116 of FIG. 3 is shown. Both the bottom leg 164 of the wear member assembly 116 and the top leg 146 can be seen. Looking at FIG. 4, it can be seen that the bottom leg 164 is shorter than the top leg 146 in a direction that is perpendicular to the sweep direction S of the front edge 135 of the work implement. The bottom surface of the bottom leg 164 has wear buttons 166 attached to it while wear pads or chocky blocks 168 are attached to the bottom surface of the throat portion 170 of the wear member assembly 116. The mounting tang 144 and the mounting aperture 148 can also be seen.

FIG. 5 shows a front view of the wear member assembly 116 of FIG. 3. The chocky blocks 150 attached to the nose 176 of the wear member assembly 116 are shown as well as the bottom chocky blocks 168 that are attached to the bottom surface of the throat portion 170 of the wear member assembly 116. The hoisting ring 152 and mounting tang 144 that extend from the top leg 146 of the wear member assembly 116 are also shown. In many embodiments, there may be a pattern of tool adapter/tool, lip shroud or other wear member assembly, tool adapter/tool, lip shroud or other wear member assembly that is repeated along at least a portion of the sweep direction S and may repeat along the entire sweep direction S. This may not be true for other embodiments and tools or tool adapters may not be present.

FIG. 6 is a side sectional view of the wear member assembly 116 of FIG. The wear member assembly 116 comprises a nose portion 176, a first leg 146, a second leg 164 and a throat portion 170 that connects the legs 146, 164 and nose portion 176 together. The first and second legs 146, 164 and throat portion 170 define a slot 190 that includes a closed end 192 and an open end 194. The slot 190 defines a direction A of assembly onto a work implement 101 (see FIG. 2 for an example). The first leg 146 is longer than the second leg 164 in the direction of assembly A and defines an aperture 148 that is configured to receive a retaining mechanism 126 (shown in FIG. 2) and that is elongated in the direction A of assembly. Thus, the wear member assembly 116 is configured to be attached to a work implement 101 using a retaining mechanism 126. Again, any method or device known or that will be devised in the art may be used to mechanically attach any of the fabricated wear member assemblies discussed herein.

The methods of any attachment may be varied as needed or desired. For this embodiment, the front lip 114 of FIG. 2 is an integrally cast member but the configuration, material and method of manufacture for the front lip may be varied as needed or desired.

Continuing to focus on FIG. 6, the details of the construction of the wear member assembly 116 will now be discussed. As already mentioned, the wear member assembly 116 is configured to be mechanically attached to a work implement assembly 100 using a retaining mechanism 126. The wear member assembly 116 comprises an upper sheet metal member 202 that is formed to a first configuration, and a buttress member 204 that forms a throat portion 170, which includes two finger portions 171, 171′ that straddle the upper and lower surfaces of the lip. The buttress member 204 is connected to the upper sheet metal member 202. The sheet metal member at least partially forms the reinforced attachment structure 206 that defines the aperture 148 that is configured to receive the retaining mechanism 126.

For this embodiment, the first configuration of the upper sheet metal member 202 includes a first bend 208 and a second bend 210. The wear member assembly 116 further comprises a lower sheet metal member 212 that is formed to a second configuration wherein the second configuration of the lower sheet metal member 212 includes a first bend 214. The lower sheet metal member 212 is also attached to the buttress member 204.

As used herein, “first configuration”, “second configuration”, “third configuration”, imply that the configurations are each different from each other. This is not necessarily case in other embodiments of the present disclosure.

As has already been described, the upper sheet metal member 202, lower sheet metal member 212, and buttress member 204 define a direction A of assembly onto a work implement assembly 100 and the upper sheet metal member 202 is longer in the direction A of assembly than the lower sheet metal member 212.

The wear member assembly 116 defines a vertical direction V that is substantially perpendicular to the direction A of assembly and the upper sheet metal member 202 defines a forward extremity 216 along the direction A of assembly. The buttress member 204 defines a lowest portion 218 along the vertical direction V, and the lower sheet metal member 212 defines a lowest portion 220 along the vertical direction V. The forward extremity 216 of the upper sheet metal member 202 is lower along the vertical direction V than the lowest portion 218, 220 of at least one of the buttress member 204 and the lower sheet metal member 212. For this embodiment, the forward extremity of the upper sheet metal member is lower than both the lowest portions of the buttress member and the lower sheet metal member. Likewise, the forward extremity 216 of the upper sheet metal member 202 is further forward along the direction A of assembly than any portion of the buttress member 204 and the lower sheet metal member 212.

It should be noted that the terms “upper” and “lower” with respect to the sheet metal members are only exemplary and that embodiments that use any orientation of the sheet metal members are contemplated to be within the scope of the present disclosure. Therefore, the terms “upper” and “lower” may be substituted with the terms “first” and “second” respectively or vice versa.

Looking now at both FIGS. 6 and 7, further features of the wear member assembly are illustrated. The wear member assembly further includes a plurality of wear components that are attached to the upper sheet metal member. These wear components take the form of wear plates 222. Also, it can be seen that the reinforcement attachment structure 206 comprises a mounting tang portion 144 of the upper sheet metal member 202 that at least partially defines the aperture 148 for receiving the retaining mechanism 126, a first wear component 224 that is attached on top of the mounting tang 144 that at least partially defines the mounting aperture 148, and a second wear component 226 that is attached on top of the first wear component 224 that at least partially defines the mounting aperture 148. The first wear component 224 includes a third sheet metal member that is formed to a third configuration that includes at least one bend 228.

As best seen in FIG. 7, the reinforcement attachment structure 206 includes the mounting tang 144 that defines an enclosed perimeter 230 of the mounting aperture 148. On the other hand, the first and second wear components 224, 226 define an open perimeter 232, 234 about the aperture 148 that is substantially U-shaped. It can also be seen that the buttress member 204 is recessed from side edges of the sheet metal members along the sweep direction S.

FIG. 8 is a rear view of the wear member assembly 116 shown in FIG. 1 in isolation from the work implement assembly 100. The following components are shown that have already been discussed. The upper sheet metal member 202 is attached to the buttress member 204 and forms part of the reinforced attachment structure 206. The upper sheet metal member 202 includes a first and second bend 208, 210. The lower sheet metal member 212 is attached to the buttress member 204 and includes a first bend 214. The reinforced attachment structure 206 includes a first wear component 224 and a second wear component 226 that sit on top of the upper sheet metal member 202. This provides three levels of components to provide the desired wear protection and rigidity for using a mechanical fastening device. Curved portions 236 are also provided that may mate with the complimentary shaped protrusions 132 found on the front edge assembly 114 as seen in FIG. 2. In some embodiments, it is contemplated that the curved portions may mate with the protrusions, helping to prevent movement along the sweep direction S once the wear member assembly is locked onto the work implement assembly.

INDUSTRIAL APPLICABILITY

In practice, a work implement such as a bucket may be sold with a wear member assembly, retaining mechanism and a working edge according to any of the embodiments discussed herein. In other situations, a kit that includes components for retrofitting an existing work implement may be provided. In some cases, only the wear member assembly may be provided.

FIG. 9 illustrates how the wear member assembly is manufactured and assembled. A wear member assembly 116 that is configured to be mechanically attached to a work implement assembly 100 (shown in FIGS. 1 and 2) using a retaining mechanism 126, 200 (shown in FIGS. 2 and 4) is provided. The assembly 116 comprises a sheet metal member 202, 212 and a buttress member 204 that is attached to the sheet metal member 202, 212 and that forms a throat portion 170. The wear member assembly 116 may be manufactured using a process that comprises the following steps: bending the sheet metal member to form at least one bend (see step 300); and machining or casting the buttress member to form the throat portion (see step 302).

In some embodiments, the wear member assembly may further comprise a second sheet metal member 202, 212 and the process may further comprise bending the second sheet metal member to form at least one bend (see step 304). In some other embodiments, the sheet metal member may be welded or brazed to the buttress member (see step 306).

In yet further embodiments when the buttress member is machined, the step of machining the buttress member includes milling the buttress member from a piece of solid stock (see step 308). The process may further comprise layering components onto the sheet metal member, forming at least three levels of components (see step 310). For example as seen in FIG. 7, the reinforced attachment structure includes three level components including the upper sheet metal member 202, the first wear component 224, and the second wear component 226. At least the upper sheet metal member and the first wear component represent two components made from sheet metal. The second wear component may also be made from sheet metal as well. This layering technique may be employed in other areas of the wear member assembly for other embodiments.

The following is another way to describe the manufacturing and assembly process. A method of manufacturing a wear member assembly that includes a sheet metal member 202, 212 and a rigid member 204 may comprise the following steps: forming the sheet metal member to a first configuration (see step 312) and casting or machining the rigid member to a second configuration (see step 314). In some embodiments, the rigid member may be a buttress member that forms the throat portion of the wear member assembly but other components of the wear member assembly may be rigid and be formed by casting or machining. The rigid member may be any member that is not easily deformable or bendable like a sheet metal member.

The method may further comprising welding or brazing the sheet metal member to the rigid member (see step 306). In order to aid this function, components welded or brazed to each other may have offset perimeters one from another. For example as best seen in FIG. 7, the layering of the components creates steps that provide weld areas that correspond to weld perimeters 238 of the components, providing as much welding length as possible, thereby helping to maximize the strength of the bond between the components. In other embodiments, spot welds that are strategically placed may be used. In some embodiments, the machining step may include milling the rigid member out of a piece of solid stock (see step 308).

The exploded assembly view shown in FIG. 9 also illustrates how the wear member assembly 116 is assembled. First, the components are provided by machining, casting, stamping, bending, etc. Alternatively, the components are provided by selling or buying the necessary components. The first sheet metal member 202, 212 is then welded or brazed onto the buttress member 204 (see step 306) and the second sheet metal member 202, 212 is welded or brazed onto the buttress member 204 (see step 306). The reinforced attachment structure 206 is then created by laying the first wear component (224) onto the first sheet metal member 202 (see step 310) and welding or brazing them together (see step 306). The second wear component 226 is then placed on top of the first wear component 224 and is then welded or brazed onto it (see step 316). The rest of the wear plates 222, hoist ring 152, chocky blocks 150, 168 and wear buttons 166 are then attached to the first and second sheet metal components 202, 212 using a welding or brazing process (see step 318). It should be noted that slots 240 are provided on the lower sheet metal member 212 that are configured to receive the lower portions of the fingers 242 of the buttress member 204. Hence, these finger members 242 are inserted into the slots 240 before the lower sheet metal member 212 is adhered to the buttress member 204 (see step 320). After all the components have been assembled, the wear member assembly 116 is then ready for use.

As can be seen, the wear member assembly is made of disparate parts, allowing different sized wear member assemblies to be assembled. Furthermore, parts such as sheet metal components may be trimmed to size if desired before being attached to other components using a laser cutting or a water jet cutting technology, etc. The modular nature of these designs lend a versatility in the manufacture and use of these wear member assemblies that may be useful in the field when different sized and shaped wear member assemblies are desired.

It will be appreciated that the foregoing description provides examples of the disclosed assembly and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Also, the numbers recited are also part of the range.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and methods of assembly as discussed herein without departing from the scope or spirit of the invention(s). Other embodiments of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the equipment may be constructed and function differently than what has been described herein and certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps or combined. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments.

Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A wear member assembly that is configured to be mechanically attached to a work implement using a retaining mechanism, the wear member assembly comprising: a first sheet metal member that is formed to a first configuration; and a buttress member that forms a throat portion and that is connected to the upper sheet metal member; wherein the first sheet metal member at least partially forms a reinforced attachment structure that defines an aperture that is configured to receive a retaining mechanism.
 2. The wear member assembly of claim 1 wherein the first configuration of the first sheet metal member includes a first bend and a second bend.
 3. The wear member assembly of claim 1 further comprising a second sheet metal member that is formed to a second configuration wherein the second configuration of the second sheet metal includes a first bend and wherein the second sheet metal member is attached to the buttress member.
 4. The wear member assembly of claim 3, wherein the first sheet metal member, second sheet metal member, and buttress member define a direction of assembly onto a work implement and the first sheet metal member is longer in the direction of assembly than the second sheet metal member.
 5. The wear member assembly of claim 4, wherein the wear assembly defines a vertical direction that is substantially perpendicular to the direction of assembly and wherein the first sheet metal member defines a forward extremity along the direction of assembly, the buttress member defines a lowest portion along the vertical direction, and the second sheet metal member defines a lowest portion along the vertical direction, wherein the forward extremity of the first sheet metal member is lower along the vertical direction than the lowest portion of at least one of the buttress member and the second sheet metal member.
 6. The wear member assembly of claim 5 wherein the forward extremity of the first sheet metal member is lower than both the lowest portions of the buttress member and the second sheet metal member.
 7. The wear member assembly of claim 5 wherein the forward extremity of the first sheet metal member is further forward along the direction of assembly than any portion of the buttress member and the second sheet metal member.
 8. The wear member assembly of claim 1 further comprising a plurality of wear components that are attached to the first sheet metal member.
 9. The wear member assembly of claim 1 wherein the reinforcement attachment structure comprises: a mounting tang portion of the first sheet metal member that at least partially defines the aperture; a first wear component that is attached on top of the mounting tang that at least partially defines the mounting aperture; and a second wear component that is attached on top of the first wear component that at least partially defines the mounting aperture.
 10. The wear member assembly of claim 9 wherein the first wear component includes a third sheet metal member that is formed to a third configuration that includes at least one bend.
 11. A wear member assembly that is configured to be mechanically attached to a work implement using a retaining mechanism, the assembly comprising a sheet metal member and a buttress member that is attached to the sheet metal member and that forms a throat portion, wherein the wear member assembly is manufactured using a process that comprises the following steps: bending the sheet metal member to form at least one bend; and machining or casting the buttress member to form the throat portion.
 12. The wear member assembly of claim 11 further comprising a second sheet metal member, wherein the process further comprises bending the second sheet metal member to form at least one bend.
 13. The wear member assembly claim 11 wherein the process further comprises welding the sheet metal member to the buttress member.
 14. The wear member assembly of claim 11 wherein the step of machining the buttress member includes milling the buttress member from a piece of solid stock.
 15. The wear member assembly of claim 11 wherein the process further comprises layering components onto the sheet metal member, forming at least three levels of components.
 16. A method of manufacturing a wear member assembly that includes a sheet metal member and a rigid member, the method comprising: forming the sheet metal member to a first configuration; and casting or machining the rigid member to a second configuration.
 17. The method of claim 16 further comprising welding or brazing the sheet metal member to the rigid member.
 18. The method of claim 16 wherein the machining step includes milling the rigid member out of a piece of solid stock.
 19. The method of claim 16 further comprising layering components onto the sheet metal member, forming at least three levels of components.
 20. The method of claim 19 wherein at least two of the layers of components include sheet metal components. 